/**
 * jQuery json-viewer
 * @author: Alexandre Bodelot <alexandre.bodelot@gmail.com>
 */
(function($){

    /**
     * Check if arg is either an array with at least 1 element, or a dict with at least 1 key
     * @return boolean
     */
    function isCollapsable(arg) {
      return arg instanceof Object && Object.keys(arg).length > 0;
    }
  
    /**
     * Check if a string represents a valid url
     * @return boolean
     */
    function isUrl(string) {
       var regexp = /^(ftp|http|https):\/\/(\w+:{0,1}\w*@)?(\S+)(:[0-9]+)?(\/|\/([\w#!:.?+=&%@!\-\/]))?/;
       return regexp.test(string);
    }
  
    /**
     * Transform a json object into html representation
     * @return string
     */
    function json2html(json, options) {
      var html = '';
      if (typeof json === 'string') {
        /* Escape tags */
        json = json.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;');
        if (isUrl(json))
          html += '<a href="' + json + '" class="json-string">' + json + '</a>';
        else
          html += '<span class="json-string">"' + json + '"</span>';
      }
      else if (typeof json === 'number') {
        html += '<span class="json-literal">' + json + '</span>';
      }
      else if (typeof json === 'boolean') {
        html += '<span class="json-literal">' + json + '</span>';
      }
      else if (json === null) {
        html += '<span class="json-literal">null</span>';
      }
      else if (json instanceof Array) {
        if (json.length > 0) {
          html += '[<ol class="json-array">';
          for (var i = 0; i < json.length; ++i) {
            html += '<li>';
            /* Add toggle button if item is collapsable */
            if (isCollapsable(json[i])) {
              html += '<a href class="json-toggle"></a>';
            }
            html += json2html(json[i], options);
            /* Add comma if item is not last */
            if (i < json.length - 1) {
              html += ',';
            }
            html += '</li>';
          }
          html += '</ol>]';
        }
        else {
          html += '[]';
        }
      }
      else if (typeof json === 'object') {
        var key_count = Object.keys(json).length;
        if (key_count > 0) {
          html += '{<ul class="json-dict">';
          for (var key in json) {
            if (json.hasOwnProperty(key)) {
              html += '<li>';
              var keyRepr = options.withQuotes ?
                '<span class="json-string">"' + key + '"</span>' : key;
              /* Add toggle button if item is collapsable */
              if (isCollapsable(json[key])) {
                html += '<a href class="json-toggle">' + keyRepr + '</a>';
              }
              else {
                html += keyRepr;
              }
              html += ': ' + json2html(json[key], options);
              /* Add comma if item is not last */
              if (--key_count > 0)
                html += ',';
              html += '</li>';
            }
          }
          html += '</ul>}';
        }
        else {
          html += '{}';
        }
      }
      return html;
    }
  
    /**
     * jQuery plugin method
     * @param json: a javascript object
     * @param options: an optional options hash
     */
    $.fn.jsonViewer = function(json, options) {
      options = options || {};
  
      /* jQuery chaining */
      return this.each(function() {
  
        /* Transform to HTML */
        var html = json2html(json, options);
        if (isCollapsable(json))
          html = '<a href class="json-toggle"></a>' + html;
  
        /* Insert HTML in target DOM element */
        $(this).html(html);
  
        /* Bind click on toggle buttons */
        $(this).off('click');
        $(this).on('click', 'a.json-toggle', function() {
          var target = $(this).toggleClass('collapsed').siblings('ul.json-dict, ol.json-array');
          target.toggle();
          if (target.is(':visible')) {
            target.siblings('.json-placeholder').remove();
          }
          else {
            var count = target.children('li').length;
            var placeholder = count + (count > 1 ? ' items' : ' item');
            target.after('<a href class="json-placeholder">' + placeholder + '</a>');
          }
          return false;
        });
  
        /* Simulate click on toggle button when placeholder is clicked */
        $(this).on('click', 'a.json-placeholder', function() {
          $(this).siblings('a.json-toggle').click();
          return false;
        });
  
        if (options.collapsed == true) {
          /* Trigger click to collapse all nodes */
          $(this).find('a.json-toggle').click();
        }
      });
    };
  })(jQuery);